1. Field of the Invention
The present invention relates to a Compact Peripheral Component Interconnect (“CPCI”) computer system. More particularly, the present invention relates to a CPCI system that is adapted for dynamic replacement of a hot swap controller.
2. Description of Related Art
CPCI is a high performance industrial bus based on the standard PCI electrical specification in rugged 3U or 6U Eurocard packaging. CPCI is intended for application in telecommunications, computer telephony, real-time machine control, industrial automation, real-time data acquisition, instrumentation, military systems or any other application requiring high speed computing, modular and robust packaging design, and long term manufacturer support. Because of its extremely high speed and bandwidth, the CPCI bus is particularly well suited for many high-speed data communication applications such as servers, routers, converters, and switches.
Compared to standard desktop PCI, CPCI supports twice as many PCI slots (8 versus 4) and offers a packaging scheme that is much better suited for use in industrial applications. Conventional CPCI cards are designed for front loading and removal from a card cage. The cards are firmly held in position by their connector, card guides on both sides, and a faceplate that solidly screws into the card cage. Cards are mounted vertically allowing for natural or forced air convection for cooling. Also, the pin-and-socket connector of the CPCI card is significantly more reliable and has better shock and vibration characteristics than the card edge connector of the standard PCI cards.
Conventional CPCI defines a backplane environment that is limited to eight slots. More specifically, the bus segment of the conventional CPCI system is limited to eight slots, which includes a system slot and peripheral slots. The system slot provides the clocking, arbitration, configuration, and interrupt processing for up to seven peripheral slots.
The newest trend in CPCI systems is to include a hot swap controller so as to support hot swappable front cards. The hot swap controller allows a user to plug and unplug a hot swappable front card while the system remains on. In other words, the hot swap controller allows a user to exchange hot swappable front cards while the system is running so that there is no need to reboot the system. The CPCI Hot Swap/HA Specification defines, among other things, that the connector-pin P1-D15 (in the backplane) and connector-pin J1-D15 (in the front card) be designated as a BD_SELECT# line. The hot swap controller drives the BD_SELECT# line to detect the insertion of a hot swappable front card into a slot of the backplane, and to power-up/power-down the front card. The Specification further defines the dynamic interface protocol between the system's hot swap controller and the front card through this line.
Although conventional CPCI systems that include the hot swap controller allow for the dynamic replacement of hot swappable front cards, they do not allow for the dynamic replacement of the hot swap controller. This means that if the hot swappable controller is defective then the CPCI system would need to be shut down to replace the defective hot swap controller, and power-cycling or resetting of the system would be required. There are many instances where shutting down the system in order to replace a defective hot swap controller would be harmful. For example, if a CPCI system is being used as part of a telecommunications system, then it is required to shut down the entire telecommunications system in order to replace the defective hot swap controller. This means that users of the system would not be able to access the system during the replacement process such that it greatly inconveniences the users of the system.
Accordingly, it would be desirable to provide a CPCI system that is adapted to provide dynamic replacement of the hot swap controller.